There are many methods to implement Ajax in Asp.net. In the past, the project used ajax2.0 assembly (ajaxpro.2.dll) to implement asynchronous communication, but it seems that ajaxpro is no longer maintained, so in the project, we gradually reference Asp.net ajax to replace ajaxpro. I only know the advantages and disadvantages of the two in the application, it is not true that we can fully understand the differences between the two in terms of implementation. We have not read their source code. However, in terms of efficiency, it seems that Asp.net Ajax is not as efficient as ajaxpro, the former transfers the control in updatepanel to the server, which is slower than ajaxpro in transmission efficiency. ajaxpro only transmits the requested data to the server and hopes to read their source code in the future, they are understanding their similarities and differences, implementation principles, and Ajax implementation, that is, jquery, which is not really used in the project. However, it seems that vs2008 has already integrated jquery, and I believe it has extraordinary advantages, I hope you can learn more about them in the future.
These Ajax implementations are different, but their final principles are the same. General steps:
1. The client triggers an Ajax event,
2. Create an instance of the XMLHTTPRequest object,
3. Send a request to the server,
4. The server responds to your request,
5. The request is returned to the client,
6. client callback Method
I read the implementation principles of ASP. NET Ajax from a blog, and I think it is good. If you are interested, please take a look.
Http://www.cnblogs.com/liuxu-wxy/archive/2007/04/25/727346.html